Method of rebuilding an oxygen lance

ABSTRACT

A method of rebuilding oxygen lance to improve the rebuilt structure is disclosed in connection with oxygen lances such as used by the steel industry in connection with introducing oxygen into open-hearth or basic oxygen furnaces containing molten steel. An oxygen lance having tubular coolant channels and an oxygen supply channel with an apertured brass casting forming the oxygen delivery tip is rebuilt to form a coolant chamber centrally of the tip of the lance and the burned away metal of the tip replaced by welding techniques. Coolant passageways in the tip portion of the lance are placed in communication with the coolant chamber for an improved cooling effect.

[ 51 July 11, 1972 [54] METHOD OF REBUILDING AN OXYGEN LANCE [72] Inventor: Grant A. Oaltes, RD. #4, Cortland. Ohio [22] Filed: Dec. 18, 1970 [21] Appl.No.: 99,570

[ ReterencesCited UNITED STATES PATENTS 2,494,970 1/1950 Shea ..219/76X Yenni et al. ..2l9/76 3,449,816 6/l969 Swiclretal ..29/402 Primary Examiner-R. F. Staubly Attorney-Webeter B. I-larpman [57] ABSTRACT A method of rebuilding oxygen lance to improve the rebuilt structure is disclosed in connection with oxygen lances such as used by the steel industry in connection with introducing ox ygen into open-hearth or basic oxygen lumaces containing molten steel. An oxygen lance having tubular coolant channels and an oxygen supply channel with an apertured brass casting forming the oxygen delivery tip is rebuilt to fonn a coolant chamber centrally of the tip of the lance and the burned away metal of the tip replaced by welding techniques. Coolant ways in the tip portion of the lance are placed in communication with the coolant chamber for an improved cooling effect.

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2. Description of the Prior Art:

Prior structures of this type comprise several long pipe sections positioned one within the other and secured at one of their ends to an apertured casting. The long pipes which are of different diameters provide axially extending passageways for the oxygen and outward and return eways for a liquid coolant such as water. The apertures in the casting which otherwise closes the tip of the lance communicate with the oxygen supply pipe so that the oxygen is introduced through the same into the open-hearth or BOF vessel and still other apertures establish communication between the coolant channels of the pipes to introduce some cooling eflect into the casting.

As heretofore used the casting erodes relatively rapidly as a result of its exposure to the heat and turbulence of the molten metal into which the oxygen is being introduced through the lance with the result that the area of the casting is reduced to a point where the coolant channels are opened whereupon the lance must be withdrawn from the furnace. Heretofore, such oxygen lances have been discarded after a relatively short life.

This invention provides for rebuilding such oxygen lances to render them more efficient in operation and capable of a longer life and to make possible continued reuse of the same through subsequent rebuilding operations.

SUMMARY OF THE INVENTION A method of rebuilding an oxygen lance having an eroded tip portion comprises cutting away a portion of the lance tip casting to form a coolant chamber, capping the chamber, installing plugs of suitable material in the oxygen delivery apertures in the tip portion and rebuilding the tip portion to its original configuration by welding metal thereon and subsequently removing said plugs and reshaping said tip portion.

DESCRIPTION OF THE DRAWINGS FIG. I is a cross sectional side elevation with parts broken away of the delivery end portion of an oxygen lance showing the eroded tip portion and break through into the coolant channels therein.

FIG. 2 is a side elevation of the tip portion of the oxygen lance of FIG. I showing steps in the rebuilding thereof and FIG. 3 is a cross-sectional side elevation with parts broken away showing the same after rebuilding.

DESCRIPTION OF THE PREFERRED EMBODIMENT In its simplest form the method of rebuilding an oxygen lance disclosed herein comprises welding replacement metal in the eroded area of the tip portion of the oxygen lance.

By referring to FIG. I of the drawings the tip portion of an oxygen lance may be seen to comprise a casting l usually formed of bronze and which casting I0 is carried on the outermost or free ends of a plurality of tubes 11, I2 and [3 respectively.

The ends of the tubes 1 I, 12 and 13 are affixed to the casting as by welding. The tubes ll, 12 and 13 are usually about 60 feet long and their opposite end, not shown, are engaged in a manifold through which a coolant such as water and a supply of oxygen are placed in communication with the lance.

The oxygen is delivered to the tip of the oxygen lance through the tube 11 which is welded as at 14 to an upstanding central portion [5 of the casting l0 and the oxygen flows through passageways 16 in the casting I0 and thus outwardly of the lance and into the molten metal in the open-hearth or basic oxygen furnace in which the lance is used.

The tube 13 is welded in a watertight manner to the casting 10 as by the weld l7 and water introduced into the opposite or manifold end of the tube 13 will flow downwardly and is able to enter cooling bores 18 in the casting 10 by way of tubular connections 19 which extend through the tube 12 and into the casting 10. Return coolant bores 20 establish communication between the coolant bores 18 and the area within the tube 11 and it will be observed that coolant is circulated through the central portion of the casting 10 by the plurality of radially positioned coolant bores 18 and 20. The end ofthe tube 12 is engaged in annular groove 21 in the casting 10.

Still referring to FIG. 1 of the drawings it will be observed that the end ofthe tube 12 is spaced with respect to the bottom of the annular groove 21 in the casting 10 by a plurality of spacing members 22 so that coolant within the tube 13 can move in under the end of the tube 12 and flow outwardly therethrough. Arrows in FIG. I of the drawings indicate the direction of flow of the coolant and it will be observed that the annular groove 21 in the casting 10 forms a cooling chamber within the same.

In FIG. I of the drawings the eroded end surface of the oxygen lance and specifically the lower portion of the casting 10 is indicated by the letter E and it will be observed that at the maximum point of erosion the metal of the casting 10 has been removed to a point where the lowermost areas of the coolant bores 18 and 20 are exposed as indicated in FIG. I by the letter 5.

Those skilled in the art will observe that the oxygen lance heretofore described in connection with FIG. I is a conventional oxygen lance such as being used by the steel industry and that when failure has occurred as at point B in FIG. I the lance is no longer usable.

In rebuilding the oxygen lance and more specifically the casting 10 comprising the tip thereof by the method disclosed herein, several successive steps are taken as follows and as illustrated in FIGS. 2 and 3 of the drawings.

By referring to FIG. 2 it will be seen that a portion of the casting 10 of FIG. I is disclosed in cross section and that shaped graphite plugs 13 have been inserted in each of the oxygen passageways l6 in the casting l0 and that the plugs 23 are of a length greater than the original length of the pways as determined by the original end configuration of the oxygen lance and as shown for example by the broken lines in FIG. 1 of the drawings which describe the arcuate end portion 26 of the lance as it originally existed.

Still referring to FIG. 2 of the drawings, it will be seen that a chamber 24 has been formed in the eating 10 in the area defined by the junction of the coolant bores 18 and 20 and which area was indicated in FIG. I by the letter B. A cap 25 is applied as a closure to the coolant chamber 24 by positioning the same on an annular shoulder formed therein.

The eroded area of the casting I0 is then rebuilt by the application of metal as by welding until the eroded area is completely filled. It will be observed that the metal applied in the build up step of the method of rebuilding the oxygen lance tip will be positioned around and about the graphite plugs 23 so that the oxygen passageways 16 are retained in their original form and over the cap 25 so that an effective seal is insured.

It will be further observed that the coolant chamber 24 is now considerably larger than the junction area of the coolant bores 18 and 20 in the original form of the casting l0 and that as a result of its increased area the rebuilt casting 10 forms a more eflicient tip end of the oxygen lance. The coolant chamber 24 may obviously be larger than illustrated in FIG. 2 of the drawing as it may include radial extensions between the several oxygen delivery passageways l6 and in any event, the coolant is introduced into a wider area in the rebuilt casting 10 than was possible in its original form.

It will further be observed that the coolant chamber 24 is in the area of the maximum erosion of the metal of the casting and that it is capable therefore of maintaining this portion of the casting at a lower temperature than in the original form of the casting forming the tip of the oxygen lance and that the life expectancy of the rebuilt oxygen lance and particularly the tip thereof, is thus greatly increased.

By referring now to FIG. 3 of the drawings a cross sectional side elevation of a rebuilt oxygen lance and particularly the tip thereof may be seen and it will be observed that the oxygen delivery passageways 16 extend to the end surface 27 of the rebuilt tip. A broken line 28 in the cross sectional representation of the casting indicates the weld junction of the rebuilt metal with the metal of the original casting 10.

It will be observed that the rebuilt casting 10 has been restored to its original configuration as by machining and that the graphite plugs 23 as seen in FIG. 2 of the drawings which were present during the rebuilding operation have been removed. The cap 25 remains in position forming a wall of the coolant chamber 24 as heretofore described. Arc welding under inert gas may be employed.

The above described method of rebuilding the eroded tip portion of an oxygen lance will thus be seen to provide a of the junctions of the coolant bores therein as be drilling into the area and then capping and/or plugp'ng the drilled opening used to form the coolant chamber.

Although but one embodiment of the present invention has been illustrated and described it will be apparent to those skilled in the art that various changes and modifications in the method and article herein disclosed may be made therein without departing from the spirit of the invention and having thus described my invention what I claim is:

I claim:

I. The method of rebuilding an eroded metal tip portion of a used oxygen lance having oxygen delivery pmagewsys therethrough and coolant bores therein and having a known original configuration, comprising forming a coolant chamber cavity in said eroded tip in communication with said coolant bores, closing said cavity, placing axially extending non-metallic forrm partially in said oxygen delivery passageways to extend said passageways, adding metal to said eroded tip portion around said forms to increase the size of said tip and reshape rebuilt lance and more particularly the end casting thereof same orifliml confilul'adonand "lemma that is improved with respect to the original form thereof and which rebuilt oxygen lance will have a substantially greater life in its reuse cycle than that of the original lance tip.

Those skilled in the art will recognize that an improved product results from the method described herein and which product may be formed as a new oxygen lance tip for first time use if so desired and which new product would incorporate the coolant chamber 24 formed in the original casting [0 of a new oxygen lance tip by forming the coolant chamber in the area said forms.

2. The method of claim I wherein said coolant chamber is formed by removing metal from said eroded body member in the area of said coolant bores.

3. The method of claim 1 wherein said metal is added to said body member by welding the same thereon.

4. The method of claim I wherein said metal is added to said body member by arc welding in an inert gas atmosphere.

i i 1! I 

1. The method of rebuilding an eroded metal tip portion of a used oxygen lance having oxygen delivery passageways therethrough and coolant bores therein and having a known original configuration, comprising forming a coolant chamber cavity in said eroded tip in communication with said coolant bores, closing said cavity, placing axially extending non-metallic forms partially in said oxygen delivery passageways to extend said passageways, adding metal to said eroded tip portion around said forms to increase the size of said tip and reshape the same to its original configuration, and thereafter removing said forms.
 2. The method of claim 1 wherein said coolant chamber is formed by removing metal from said eroded body mEmber in the area of said coolant bores.
 3. The method of claim 1 wherein said metal is added to said body member by welding the same thereon.
 4. The method of claim 1 wherein said metal is added to said body member by arc welding in an inert gas atmosphere. 